Abstract

This process—above threshold ionization (ATI)—is when an atom placed in an intense optical field absorbs s more photons than the minimum number n necessary to reach the ionization limit I₀. In this process many peaks are observed in the photoelectron spectrum; and in the usual experimental conditions of a long laser pulse, the peaks are found to have relatively narrow widths and energies given by E = (n + s)ħω – I₀.

© 1987 Optical Society of America